The recovery of heat from solar radiation is usually carried out by thermal solar panels which convert the solar radiation into heat.
These panels consist of a frame having a planar or tubular sensor designed to reheat the heat transfer fluid.
These panels have drawbacks.
More specifically, said panels require the use of metal materials and the production of a heavy frame which is costly to produce.
The panels weigh down the roof, causing repairs to the seal of the roof, the delicate operation thereof potentially causing leakages.
Moreover, it is questionable whether said solar panel systems have an attractive appearance on roofs.
In many instances, town planning regulations make the installation thereof impossible. This is the case, in particular, in the vicinity of buildings registered as historic monuments.
More discrete recovery systems have been created in order to respond to the aesthetic requirements of buildings.
Some systems comprise recovery devices which are located on the underside of the roof and which use metal elements connected to the heat transfer network.
The roof elements thus behave in the manner of an external facing, the appearance thereof being preserved.
The major drawback is the creation of an additional part to produce the connection between the roof and the heat transfer network which increases the complexity of the installation and creates additional material, increasing the cost and environmental impact. The amount of grey energy is substantially increased.
Recovery systems made of synthetic materials have also been created and reproduce the appearance of traditional materials. Said systems use synthetic materials as absorbers and have drawbacks relating to the duration of the service life of the panels, the recycling of products and the use of products derived from the chemical or petroleum industry for their production.
Further systems use air as the heat transfer medium.
Air naturally rises underneath roofs as a result of heating. The roof elements transmit their heat to the air.
This system has further drawbacks: it is difficult to exploit this heat. More specifically, to utilize this hot air and to distribute this heat to the user, it is necessary to use an air circulation system which is bulky and costly or to add air/water heat exchangers for the use thereof as primary fluid. For example, this might be for the preparation of domestic hot water.